The Federalist Papers are a series of 85 articles about the United States Constitution, first published serially in New York City newspapers (the Independent Journal, the New-York Packet and the Daily Advertiser) between October 27, 1787 and May 28, 1788. A compilation, called The Federalist, was published in 1788.

The Federalist Papers serve as a primary source for interpretation of the Constitution. They also outline the philosophy and motivation of the proposed system of government, as it was presented by Madison, Hamilton, and Jay. The authors of the Federalist Papers were not above using the opportunity to provide their own "spin" on certain provisions of the constitution to (i) influence the vote on ratification and (ii) influence future interpretations of the provisions in question.

Federalist No. 10 and Federalist No. 51 are generally regarded as the most influential of the 85 articles; 10 advocates for a large, strong republic, 51 explains the need for separation of powers.